From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (ext-mx13.extmail.prod.ext.phx2.redhat.com [10.5.110.18]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q25AKZMx028454 for ; Mon, 5 Mar 2012 05:20:35 -0500 Received: from mail-ee0-f46.google.com (mail-ee0-f46.google.com [74.125.83.46]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q25AKXxm020881 for ; Mon, 5 Mar 2012 05:20:34 -0500 Received: by eekc41 with SMTP id c41so1417221eek.33 for ; Mon, 05 Mar 2012 02:20:33 -0800 (PST) Message-ID: <4F54936E.8030801@profitbricks.com> Date: Mon, 05 Mar 2012 11:20:30 +0100 From: Sebastian Riemer MIME-Version: 1.0 References: <4F50CEB1.7040601@profitbricks.com> <20120302171712.GA14405@redhat.com> In-Reply-To: <20120302171712.GA14405@redhat.com> Content-Transfer-Encoding: 7bit Subject: Re: [linux-lvm] LVM Thin Provisioning size limited to 16 GiB? Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii" To: Mike Snitzer Cc: LVM general discussion and development On 02/03/12 18:17, Mike Snitzer wrote: >> >> I've also tested to explicitly set the --poolmetadatasize to 16 GiB and >> the data pool to 100 GiB, but same result. I also did some benchmarks. >> Performance wasn't that bad, but could be really better (at least doubled). >> > > You haven't actually shown how you attempted to make use of a 100GB and > 16GB metadatasize. > > But the maximum metadata device size is 17112760320 sectors (or 15.9375 > GB). > > So try with 15GB (even though that is way larger than you need for 100GB > of data). I've tried these commands: vgcreate test /dev/md/test* lvcreate -i 12 -I 64 -L 100G --poolmetadatasize 16G -T test/pool I don't see any chance to select the meta-data device in LVM like it is possible with dmsetup. >> Here are my commands: >> vgcreate test /dev/md/test* >> lvcreate -i 12 -I 64 -L 16G -T test/pool >> lvcreate -V 45G -T test/pool -n test00 This is like it is described in the man page of lvcreate. There it is documented as a single lvcreate command. This creates five dm devices in /dev/mapper: test-pool: 16,106,127,360 Bytes, 254:3, table: 0 31457280 linear 254:2 0 test-pool_tdata: 16,106,127,360 Bytes, 254:1, table: 0 31457280 striped 12 128 9:127 2048 9:126 2048 9:125 2048 9:124 2048 9:123 2048 9:122 2048 9:121 2048 9:120 2048 9:119 2048 9:118 2048 9:117 2048 9:116 2048 test-pool_tmeta: 4,194,304 Bytes, 254:0, table: 0 8192 linear 9:116 2623488 test-pool-tpool: 16,106,127,360 Bytes, 254:2 table: 0 31457280 thin-pool 254:0 254:1 128 0 0 test-test00: 48,318,382,080 Bytes, 254:4, table: 0 94371840 thin 254:2 1 >> Seems like pool meta-data and pool data aren't separated at current >> development state. > > But in the above test, you've created a striped LV named /dev/test/pool > of 16GB. > > And you've written 11GB to the test00 thin device. And you're running > out of metadata space. > > This implies to me that LVM2's size guesstimate for the proper data vs > metadata size split for a 16GB volume isn't conservative enough > (relative to metadata size). > > Anyway, showing your 'dmsetup table' output would be helpful in the > future. The meta-data is on one of the striped devices used for the data. This is wrong. LVM should support selecting a separate meta-data device! Sebastian